EFFECTS OF META-CHLOROPHENYLPIPERAZINE ON CEREBRAL BLOOD-FLOW IN OBSESSIVE-COMPULSIVE DISORDER AND CONTROLS

Background: A number of studies have shown that the serotonin receptor agonist meta-chlorophenylpiperazine (mCPP) can exacerbate symptoms in patients with obsessive-compulsive disorder (OCD), The aim of the pre sent study was to study the effect of this compound on regional cerebr al bloodflow (rCBF) in patients and controls. Methods: Seven OCD patie nts and 8 healthy controls were randomly allocated to a double-blind c hallenge study with mCPP (0.5 mg/kg orally). rCBF was measured by (99m )-Tc-hexamethyl-propyleneamineoxime single photon emission computed to mography. Results: mCPP did not induce OCD symptoms in patients, but c aused a significant decrease in rCBF in OCD patients, but not in contr ols. The decrease was seen in the reference regions cerebellum and who le brain, and in the frontal cortex, caudate nucleus, putamen, and tha lamus. Conclusions: The effect of mCPP on the reference regions in pat ients posed methodological problems in the normalization methods. A po ssible role of the cerebellum in OCD is discussed. (C) 1998 Society of Biological Psychiatry.